Midlife

The accessory 3 prong plug mentioned above was an option, so it might not exist on Wally A's car. I think what he is looking for is a RUN-only line that he can just plug into. There is no such thing on a 69 or 70. You'll need to find a green/red wire coming from the ignition plug and tap into that, or find the ACC 3 prong plug fuse buss extender. I just got 3 of them in stock.

Be careful: adjusting the steering box adjuster nut more than what is listed in the Shop Manual can damage the worm gear and the bearings.

It's been awfully quiet in here the past couple of days...

Super!

Circuit breaker is not a substitute for a fusible link, as with a massive short, it will simply switch on and off repeatedly. I believe (please don't quote me) that the fusible link needs to be 4 AWG sizes larger than the main power line.

That fusible link is not a factory correct 1970, as in my experience (close to 125 1970 refurbishments), I have never seen the green flag on any of the power leads: just a black wire, perhaps with some writing on it. The flags first appear in 1971. There is another useful thing about fusible links that I failed to mention above: if the car is sitting in a garage, not on, and somehow a massive short is initiated, the fusible link will prevent current flowing from the battery and thus the rest of the wiring is protected to a certain degree. It will definitely stop an electrically induced fire when the car is off or the key is in ACC or RUN but with the engine not running. Perhaps that was the reason it was implemented. As far as wire gauges go, what Ford used and documented is somewhat inconsistent with what is typically found today in wire sizes. I suspect there was either a change in AWG specifications or Ford used a slightly different gauging system that what is currently used today. When I buy 18 gauge wiring, it is somewhat thicker than the Ford product when the insulation is removed. The fusible link does appear to be about 2-4 AWG sizes less than the main power line.

Yes on both accounts. I'm not sure whether the 38A wiring is just standard copper stands or something different.

Fusible links were put in place to protect the battery and nothing else. In 1970, they were introduced, but if the car was running, there was still a hard wire from the alternator output to the entire car. The fusible link was the last 9 inches of wire from the alternator to the battery. If the link blew (let's say due to an overcharging alternator), the car will still run and the remaining wires would or would not handle the current load. When the car stopped running, the battery would now be out of the circuit (due to blown fusible link) and you wouldn't be able to provide power to the ignition switch to start the starter. In 1971, Mustangs still had fusible links, but those cars that had ammeter still had a hard-wire path from the alternator directly to all wiring on the car. Those with indicator lamps that happen to blow the fusible link would immediately die. Fusible links were not well implemented, IMHO. As for your charging problems, Mach1Driver knows more than I regarding this. Once you get away from a stock system, I'm as clueless as Seattle. I agree that with a voltmeter, you can disable the indicator lamp.

Phil Severence still repairs Ford tachs. His contact information is: Phil Severance 283 Trotter Dr. Twin Falls, Idaho 83301 208-734-4535 WWW.PhidonRestorations.com

I have a good supply of 67/68's...but if you want, you can send them in. Info at http://midlifeharness.com

Yes. You really need to go out in public a bit more, ol' man.

I'm running very low on 69 and 70 underdash harnesses, the most popular year (natch!). If you have any laying around, I typically pay $50 each plus shipping. Let's keep these beasts on the road!

Plans for an additional garage?

Yes, this is the standard underdash harness without AC and without tach. I'd guess 50% of 69 Mustangs used it.

Master Parts Catalog cross-references the C9ZB-14401-AE to C9ZZ14401-A, which fits a Mustang, no AC or tach, and not for a Boss 302.